- Waynesboro Borough Authority
- Waynesboro, Pennsylvania
- Our Role
- Design Engineer, Hydrogeological, Permitting, Construction Management.
- 250 gpm
- Construction Cost
- $2.3 million
- New Construction
- 3 years 7 months
- New well increases total source water capacity and improves distribution system pressures
- Membrane filtration allows well water to be blended seamlessly with surface water source
- Customers see no discernible change in water quality or taste.
The Waynesboro Authority faced the challenge of accommodating the borough’s future water needs while minimizing the impact on their customers, who were accustomed to very soft surface water. To supplement the original surface water supply, Gannett Fleming provided hydrogeological services to develop a new well, but the new well had very high raw water hardness, compared to the surface water source.
Our team evaluated two treatment options: ion exchange softening and high-pressure membrane (nano) filtration. Although the anticipated capital costs for ion exchange were lower, the operating costs and potential health risks posed by a high amount of sodium in the water made membrane filtration the preferred choice. We designed a nanofiltration membrane treatment facility that allowed the water to be blended seamlessly, with no discernible effect on water quality or taste.
Gannett Fleming provided hydrogeological services to develop a new community well water supply source. A preliminary hydrogeologic investigation identified four test well locations, and we developed the new public supply well on the north side of the authority's service area. We also analyzed several water treatment options. Although the ion exchange offered lower capital costs, the large amount of salt needed would make operating costs higher, and the amount of sodium that would be added to the water could cause adverse health risks to customers. Membrane filtration was determined to be the most practical choice.
Our team designed the Well No. 2 membrane treatment facility. The project consisted of site work, a packaged sanitary pump station, design of a one-story masonry structure to house the facility, design of a new wastewater lift station, installation of a nanofiltration membrane system and a programmable logic controller (PLC)-based control system, and associated chemical feed systems. The project also included an upgrade to the existing water treatment plant PLC control system to provide sufficient inputs and outputs to handle the entire well station facility. The result has been a water system that meets the demands of a growing population and maintains existing water quality standards.
- Chemical feed processes associated with the membrane system include scale inhibitor and caustic soda for post-pH adjustment
- Nanofiltration membrane system treats water to obtain desired water hardness
- PLC control system has sufficient inputs and outputs to handle the entire well station facility, in addition to the membrane system.
- Well No. 2 water quality and performance are remotely monitored at the surface water treatment plant
- Membrane concentrate disposal is via sanitary sewer.
- Groundwater sustainability assessment and aquifer pumping test assessment determined the rate that available groundwater resources may be withdrawn without adversely affecting groundwater supply wells and surface water bodies
- High alkalinity of concentrate from the membranes allowed the authority to significantly reduce caustic soda usage for pH adjustment at its WWTP discharge.